Acid resisting cement and method of making



Patented Dec. 2'?, 1949 UNITED STATES CROSS REFERENCE PATENT ciu-ICE 'A ACID :RESISZBING CEMENTAND METHQD fQF MAKING :of NewJerseg No Drawing. Application April 30, 1947, Serial No. 4*5,11)0. In Great Britain June'l, 194'6 '.5 llzims. (CLUB-J4.) V

'I'his :invention :relates to acid lresisting -cements. :and Ahas for its o'biect the production of :acid resisting cements which will have a sui- Mentlylow set tolenable xproper working ofthe cement finto proper position, will then set within unreasonable period --(e. g. an `hour) to a 'fairly hard-condition, and which will then lcontinue vto iur'ther harden ifor a vconsiderable `period, and `which will resist the-action -of Vacids -(in the ccn- :to all pass a G-mesh screen, is mixed With 1` .liter of waterglass (sodium silicate solution 4of 1.35 .s. g., e. o conc aving a. 'Na2O:SiOz ratio of :about .2.70. With this Ais -homogeneously mixed 350 grs. -of commited or diluted state) for a very long time :1g lacetate. This gaven mortar-like mixture whic whether'hot or cold.

' -BCemeiits Aused for laying up acid-resisting hc'icks,rtiles,' blocks or other shapes re. gain Glover 'Mera -aoid storage tanks, vessels in Awhich strong V.onids :act :upon minerals, etc.) land cemerrts used u 1hr lining such equipment, must 'he capable of A'uvcsis'ting'action of 1acidsifor a long period.

Heretofore cements made by mixing an inert -illller-fgrggregatejle. g. finely crushed guartab "f lquartz lsand, etc.) with a lsolution of anallfali 20 ioxmdto withstand boiling Yin '10% hydrochloric :metal siiicateue. rg. -water glass) have been'used 'lrposes.

For accelerating the setting of ysuch cements, it was proposed in British Patent 551,408,^to .add

no .spread in place, and zi'fhesetting of this mixture fbeglns after S-1.20 minutes. The mass became stone-like in character :after about a xhour.

A Ipari: of-.thlsmontar-illkemass was shapenito .discseof -ammsdiameter'and let-S17 mm. thickness .;(under `hand pressure :with a-ftroweli Tand .allowed to iharden and set, for the purpose of testing. Someiof these discs -were tested and laacid, .25% 'sulfuric lacid, I80% sulfuric acid, 4and 16% mimic-.acid for 18 days, without deterioralilium. Ellhe lossin weight 'inthe discs, softested, svaszsmall.

:to such xcements Ian I kyl-esterwma jatty acid. 'u Somenf the discskwlthoutvany acid treatment) im accordance lwith our ypresent invention we 30 employ esters -of `polyhydrlc alcohols, preferably still con aming a eas one group, lwhich edbersare miscib1e'-wlth water'anclwith the silicate sdhttion. This easily gives homogeneous mix- -C Mnong the estersof polyllydricahzghols tested, E5 'glycerol diacetate (the so-called diacetin of mmmer a .g e awas v`found to mially :suitable .and mixtures .of this 'with some1 1 acetate. The former "is 'miscible with waint ,p'roportions and it iis readily possible to mix this homogeneously with a mixture of finely crushed uartz and sodium silicate, very quickly. This ester Has a slow neu ra iz g effect on the alkali in the sodium silicate solution. It appears that the ester hydrolyzes in the presence of the water of the sodium silicate solution, and the fatty acid reacts with the soda of the silicate, liberatlng S102 from the silicate which bonds the 1111er (quartz) particles together.

withfb rdum sulfate, talc alone, all with satis- *factory resum.

Example 2.-A waterglass solution of commertures, which are certain in their action. Esters 3.5 Cial grade. .cnniainlng .180 .g. .NaOH and 320 is.

SiO: per kg. was 'usedfln an experiment similar ,Stn Example l. The products produced were less satisfactory. It was apparent that 'the waterglass was'too concentrated to mix easily and 'ho- 4o mogeneously with the -li'acetin.

Example 3.-'Dhe waterglass of'Example `2 was mixed ewith'sulcient water to contain 180 grams of NaGH and 320 gr. SiO: per liter. 200 gr. of Tlnely crushed quartz, all passing a 200 mesh screen, `1D0.cc..ol this diluted waterglass and 36 U0 mum cross section nf .these .being sq. cm. The

unmolded mixture began to set in about 10 minutes, and became stone-like in about an hour. It will be seen that in this example, the amount of the diacetin would, by hydrolysis, give enough acetic acid to neutralize (react with) about EXANHNER 12 hours, at about 100 C., then Washed in dis-ftilled water, dried and weighed. This ilnal weight was considered as the dry weight of the disc. The tests on loss of weight when treated with these different acid solutions is given in the following.

table.

Table 1 Temperature 100-105 0.1'

Loss in g. per 100 g. sample immersed in- 107 257 807 10% HC1 HN; H156; H1864 -2nd day 4. 20 2. 50 3. 60 3.00 2-4th day 0. 40 0. 40 0. 40 0. 90 4-6th day. 0.50 0.30 0.30 0.35 6-8th day. 0. 20 0. 30 0. 20 0. 30 8-10th day- 0. 05 0. 10 0.15 0. 20 10-12th day 0. 05 0. 07 0. i5 0. 25 12--18th day 0. 0. 35 0. 75

Total loss: (in 18 days). 5. 60 3. 67 5. 15 5. 75

In the above table, the gures are the average of at least three samples, and are figured on the weight of the discs after the 12 hours treatment described.

The attack of 10%HC1 was also measured on flakes of the cement. which had a surface/mass ratio about four times greater than the discs (6 cm2/g. instead of 1.7 cm2/g). The erosion was not accelerated, which proves that the attack of the chemical is a volume effect.

Y The tensile strength was measured. by the usual technique employed for tests of Portland cement, on 0shaped pieces of 120 g. weight and 5 cm.2 minimal cross section. In Table 2 the tensile strength of the cement in dependence upon its "age is shown, and in Table 3 the same after various treatments. It can .be observed that the strength increases with the age oi the sample.-

Finally it should be mentioned that the cement was also used as in practice e. g. as a bonding agent between acid-proof tiles of storage vessels and found to be faultless after prolonged use.

It will be understood that in the above examples, the amount of the diacetin used, is such as we have found to be entirely satisfactory. Amounts which are up to 10-12% more or less than these preferred quantities can be used, and fairly satisfactory products formed.

We claim:

1. In the production of an acid-resisting cement from waterglass, the step of adding to a soda waterglass having a speciilc gravity of about 1.35,

a water-soluble fatty acid ester of a polyhydric alcohol selected from the group consisting of glycerol and glycol, which ester still contains at least one unesteriiied alcoholic hydroxyl group, in such amount as to react with about to about of the soda of the waterglass.

2. In the production oi.' an acid-resisting cement from waterglass, the step of adding to a soda waterglass having a specic gravity of about 1.35, a water-soluble acetic acid ester of a polyhydric alcohol selected from the group consisting of glycerol and glycol, which ester still contains at least one unesteried alcoholic hydroxyl group, in such amount as to react with about 80% to about 90% of the soda of the waterglass.

3. In the production of an acid-resisting cement from waterglass, the step of adding to a soda waterglass having a specific gravity of about 1.35, an acetic acid ester of glycerol which ester'still contains at least one unesteried alcoholic hydroxyl group in such amount as to react with about 80% to about 90% of the soda of the waterglass.

4. In the production of an acid-resisting cement from waterglass, the step of adding to a soda waterglass, having a speciic gravity of about 1.35, glycerin diacetate in such amount as REFERENCES CITED The following references are oi' record 4in the le of this patent:

FOREIGN PATENTS y Number Country Date 106,452 Austria 1927 437,718 Great Britain 1934 766,346 France 1934 182,616 Switzerland 1936 551,408 Great Britain 1943 Table 2 Tensile Days after preparation Strength Ka. cm. 1 I 14. 6 19. l 24. 7 30. 5 37. 8 v40. 3

Tensile strength in kgJitlli;2 Treatment Fresh 30 days old sample sample 2 days 107 HCl (at 100 C.) 25.5 35. 3 14 days 1 o HC1 (at 100 0.)..- 38.5 2 days 25 0 H|SO4 (at 100 C.) 37.5 i day heating in nir (at C.) 47.8 70 

